JP4893216B2 - Network management device, bandwidth control method, and program - Google Patents

Description

  The present invention relates to a bandwidth control method, and more particularly to a bandwidth control method in a wireless LAN multihop network.

  With the spread of IEEE802.11b, a, g, which is a standard for wireless LAN (Local Area Network), wireless LANs are widely used in businesses and homes.

  In recent years, wireless LANs are being used in real-time traffic communications such as VoIP (Voice over Internet Protocol) in addition to conventional data communications applications in wireless LANs. Since real-time traffic such as VoIP suffers from a significant deterioration in quality due to delay and packet loss, QoS (Quality of Service) control such as bandwidth reservation is required.

  However, in a wireless LAN multi-hop network, VoIP traffic is generated from a plurality of access points (APs), and the situation becomes more complicated as traffic passes through a wireless link, so it is difficult to formulate QoS.

  In addition, RSVP (Resource reServation Protocol), which is a protocol for performing network bandwidth reservation, is standardized by IETF (Internet Engineering Task Force). There is a problem that it does not work unless all access points support it. RSVP is a protocol that reserves a bandwidth to a transmission destination on a network and ensures communication quality. The IETF is an organization that standardizes technologies used on the Internet such as TCP / IP (Transmission Control Protocol / Internet Protocol).

  In addition, a method has been proposed in which the amount of traffic is measured and band control is performed when the amount of traffic exceeds a threshold value. However, in this patent, there is a problem that it is necessary to monitor the amount of traffic at any time, and because the traffic is not classified, the bandwidth of the VoIP traffic is also controlled at the time of congestion.

  In many cases, TCP is used for data traffic that occupies most of the traffic. TCP flow, after sending the packet, it is judged that the transmission was successful by the response (ACK) from the receiver side, the own transmission rate is increased, and when there is no response or when it is judged that the packet is lost, Reduce the transmission rate of. Therefore, the TCP flow has a property of self-clocking that becomes a transmission rate according to the bottleneck link of the network.

  As described above, real-time communication such as VoIP has a large influence on quality due to delay and packet loss, and requires QoS control. One method for performing QoS control is traffic control for controlling traffic flowing in the network, such as VoIP communication and data traffic.

  Further, a portal usually exists in a multi-hop wireless network, which becomes a bottleneck link. In a multi-hop wireless network, a portal becomes a bottleneck link, and it is necessary to eliminate the bottleneck.

As a related technique, Japanese Patent Laid-Open No. 2001-298472 (Patent Document 1) discloses a band control device and a traffic control method.
In this prior art, the bandwidth control apparatus is installed between a backbone network and a plurality of local area networks (LANs), and a traffic control means for packet communication performed by a plurality of communication terminals connected to the LAN via the backbone network. In the bandwidth control device provided, the congestion detection means for detecting congestion for each of a plurality of LANs from the packet signal input to the bandwidth control device, and the amount of packet communication traffic performed by the terminal connected to the LAN via the backbone network Traffic control means for controlling is provided.

Japanese Laid-Open Patent Publication No. 2002-344531 (Patent Document 2) discloses a communication band securing and releasing request method.
In this prior art, an IP telephone network includes a router device capable of securing a bandwidth used for communication between terminals and releasing used bandwidth, an IP network composed of a plurality of the router devices, and a telephone. One or more telephone networks to which terminals are connected; a gatekeeper device connected to the IP network; one or more IP telephone gateway devices each connecting the IP network and the telephone network; and the IP network And one or more IP telephone terminals connected to each other. In this prior art communication band securing method, when communicating between IP telephone gateway apparatuses, between IP telephone terminals, or between an IP telephone terminal and an IP telephone gateway apparatus, the gatekeeper apparatus A callee IP phone gateway or callee IP phone terminal corresponding to the callee telephone number associated with the communication request received from the phone gateway or caller IP phone terminal is obtained. If the communication bandwidth reserved on the communication path between the originating and destination IP telephone gateways or IP telephone terminals is less than the total communication bandwidth after the connection based on the communication request is established, Is requested to secure an additional bandwidth with a pre-designated additional bandwidth that is larger than the communication bandwidth required for communication. The request result is notified to the originating IP telephone gateway or the originating IP telephone terminal of the terminating IP telephone gateway or the terminating IP telephone terminal.

Japanese Unexamined Patent Application Publication No. 2003-124956 (Patent Document 3) discloses a communication control method and a network system.
In this prior art, the communication control method in a network in which at least two types of first and second traffic are mixed is compared with the second traffic for the first traffic out of the traffic flowing into the first node. Transmission is performed preferentially and flow control is executed for the second traffic.

JP 2001-298472 A Japanese Patent Laid-Open No. 2002-344531 JP 2003-124756 A

An object of the present invention is to provide a bandwidth control method for performing traffic control by bandwidth control in a multi-hop wireless LAN system having one portal.
Another object of the present invention is to provide a bandwidth control method capable of limiting the traffic of a TCP flow flowing through a network by performing bandwidth control.

  In the following, means for solving the problem will be described using the numbers used in [Best Mode for Carrying Out the Invention] in parentheses. These numbers are added to clarify the correspondence between the description of [Claims] and [Best Mode for Carrying Out the Invention]. However, these numbers should not be used to interpret the technical scope of the invention described in [Claims].

  The network management device (100) of the present invention is a network management device in a wireless LAN multi-hop network, and includes a priority queue (103), a non-priority queue (104), and a bandwidth control unit (105). The priority queue (103) is a queue for priority traffic. The non-priority queue (104) is a queue for non-priority traffic. The bandwidth control unit (105) is connected to the non-priority queue (104), and performs bandwidth control for non-priority traffic in the wireless LAN multi-hop network to secure a bandwidth for priority traffic.

  The network management device (100) of the present invention further includes a count management unit (107). The count management unit (107) counts and manages the number of access points connected downstream in the wireless LAN multi-hop network. The bandwidth control unit (105) estimates the amount of priority traffic based on the number of access points, and performs bandwidth control on non-priority traffic.

  The bandwidth control unit (105) performs bandwidth control such that D ≦ B−V for the bandwidth control rate D, the bottleneck link bandwidth B, and the priority traffic bandwidth V.

  The bandwidth control unit (105) performs bandwidth control so that the bandwidth control rate is set to D / 2 or less when non-priority traffic flows bidirectionally through the network.

  The bandwidth control unit (105) determines the bandwidth V of the priority traffic based on the number of access points.

  The bandwidth control method of the present invention includes (a1) a step of checking whether a packet exists in the priority queue (103) when the portal node starts packet transmission processing, and (a2) in the priority queue (103). If the packet exists, the portal node transmits the packet in the priority queue (103); and (a3) If the packet does not exist in the priority queue (103), the portal node 104) checking whether there is a packet; and (a4) if there is a packet in the non-priority queue (104), the portal node has a non-priority traffic transmission rate equal to or lower than the bandwidth control rate. (A5) If the transmission rate of non-priority traffic is equal to or lower than the bandwidth control rate, portal no Transmitting a packet in the non-priority queue (104), and (a6) when no packet exists in the non-priority queue (104), or when the transmission rate of non-priority traffic is not less than the bandwidth control rate. The portal node ending the packet transmission process.

  The bandwidth control method according to the present invention includes (b1) a step of counting and managing the number of access points connected downstream, and (b2) a bandwidth for non-priority traffic by estimating the traffic volume of priority traffic based on the number of access points. And a step of performing control.

  The bandwidth control method of the present invention further includes the step of (c1) performing bandwidth control so that D ≦ B−V for the bandwidth control rate D, the bottleneck link bandwidth B, and the priority traffic bandwidth V. .

The bandwidth control method of the present invention further includes a step (d1) of performing bandwidth control so that the bandwidth control rate is set to D / 2 or less when non-priority traffic flows bidirectionally in the network.

The bandwidth control method of the present invention further comprises the step of (e1) determining the bandwidth V of the priority traffic based on the number of access points.

  The program of the present invention causes a computer to execute the above-described bandwidth control method.

  By performing bandwidth control for non-priority data traffic at a single node, the total non-priority traffic passing through the nodes can be kept below the bandwidth control rate, so bottlenecks can be eliminated and priority traffic can be eliminated. It will be possible to secure a bandwidth to. Also, since there is only one route to the outside, only one node needs to perform bandwidth control, which can be easily implemented.

  The present invention estimates the amount of VoIP traffic from the number of access points (AP) in a network in a wireless LAN multi-hop network composed of one portal (connection point between a wired network and a wireless network), and concentrates the traffic. This is a method of controlling the data traffic flowing in the network so as not to affect the VoIP traffic by performing bandwidth control at the node.

A first embodiment of the present invention will be described below with reference to the accompanying drawings.
The network topology of the present invention is shown in FIG. Referring to FIG. 1, the wireless LAN multi-hop network includes a portal node (P) 100, an access point (AP) 200, and an access point (AP) 300.

  The portal node (P) 100 communicates with the access point (AP) 200 by radio. Further, it communicates with an external network by wire or wireless.

  Connected to the access point (AP) 200 are VoIP terminals V11 to V1x (x is arbitrary), data terminals D11 to D1x, and an access point (AP) 300. To the access point (AP) 300, VoIP terminals V21 to V2x and data terminals D21 to D2x are connected. Communication between the portal node (P) 100 and the access point (AP) 200, between the access point (AP) 200 and the access point (AP) 300, and between terminals connected to each access point (AP) is performed by radio. .

FIG. 2 shows a basic configuration of the portal node (P) 100.
The portal node (P) 100 includes an input link 101, a packet processing unit 102, a priority queue 103, a non-priority queue 104, a bandwidth control unit 105, an output link 106, and an access point (AP) count management unit 107. Is provided.

  The input link 101 receives a packet from an access point (AP) by radio. The packet processing unit 102 distributes a packet scheduled to be transmitted to the priority queue 103 or the non-priority queue 104. The priority queue 103 stores packets to be transmitted with priority. The non-priority queue 104 stores packets that need not be transmitted with priority. The bandwidth control unit 105 performs bandwidth control for non-priority traffic. That is, the available line capacity (communication speed) is limited for each type of packet stored in the non-priority queue 104. At this time, the optimum bandwidth control rate is set from the bandwidth required for the priority traffic and the bandwidth of the bottleneck link in the network. The output link 106 transmits the packet stored in the priority queue 103 or the non-priority queue 104 to the access point (AP) by radio. The access point (AP) count management unit 107 manages the number of access points (AP) connected downstream. In this embodiment, the portal node (P) 100 has an access point (AP) function, but may not have an access point (AP) function.

  Here, the optimum bandwidth control rate, that is, the maximum value of the rate D to be set, is B for the bandwidth between the portal node (P) and the access point (AP) 200 serving as the bottleneck link, and V for the priority traffic bandwidth. Then, D ≦ B−V because of the constraint condition of B ≧ V + D. However, since the wireless LAN is half-duplex communication, when non-priority traffic flows through the network in both directions, the setting rate is D / 2 or less, which is half of the setting rate. The bandwidth V reserved for priority traffic is determined by the number of access points (AP) held by the access point (AP) count management unit 107.

  The access point (AP) 200 and the access point (AP) 300 shown in FIG. 1 include a plurality of transmission / reception units as shown in FIG. For example, the access point (AP) 200 includes wireless communication units 201, 202, and 203. The access point (AP) 300 includes wireless communication units 301, 302, and 303. The access point (AP) 200 and the access point (AP) 300 have the same configuration as that of a standard access point (AP) except that a plurality of wireless communication units are provided.

  Here, the wireless communication unit 201 communicates with the VoIP terminals V11 to V1x wirelessly. The wireless communication unit 202 communicates with the portal node (P) 100 wirelessly. The wireless communication unit 203 communicates wirelessly with the wireless communication unit 301 and the data terminals D11 to D1x. Similarly, the wireless communication unit 301 communicates with the VoIP terminals V21 to V2x wirelessly. The wireless communication unit 302 communicates with the wireless communication unit 201 wirelessly. The wireless communication unit 303 communicates with the data terminals D21 to D2x by radio.

The operation of this embodiment will be described below.
Here, in the network shown in FIG. 1, packets pd1 and pv1 destined to the outside transmitted from the data terminal D21 and VoIP terminal V21 connected to the access point (AP) 300 are connected to the access point (AP) 300, the access point (AP AP) 200 is reached via portal node (P) 100.

FIG. 3 shows a packet transmission procedure in the portal node (P) 100.
(1) Step S101
The portal node (P) 100 starts packet transmission processing.
(2) Step S102
The portal node (P) 100 checks whether a packet exists in the priority queue 103.
(3) Step S103
If there is a packet in the priority queue 103, the portal node (P) 100 transmits the packet in the priority queue 103.
(4) Step S104
If there is no packet in the priority queue 103, the portal node (P) 100 checks whether there is a packet in the non-priority queue 104.
(5) Step S105
If there is a packet in the non-priority queue 104, the portal node (P) 100 checks whether the transmission rate of the non-priority traffic is equal to or less than the bandwidth limit value (band control rate).
(6) Step S106
The portal node (P) 100 transmits a packet in the non-priority queue 104 if the transmission rate of the non-priority traffic is equal to or less than a bandwidth limit value.
(7) Step S107
The portal node (P) 100 ends the packet transmission process when there is no packet in the non-priority queue 104 or when the transmission rate of the non-priority traffic is not less than the bandwidth limit value.

  Therefore, in the packet transmission procedure at the portal node (P) 100, first, pv1 belonging to the priority traffic is preferentially transferred to the external network. On the other hand, the non-priority traffic pd1 is transferred to the external network when the priority traffic queue is empty and the current non-priority traffic transmission rate is equal to or lower than the bandwidth control rate. Therefore, the transmission rate of the data terminal D1 is automatically limited by the transfer rate at the portal node (P) 100. Even when the number of terminals transmitting data increases, the transmission rate of the entire data terminal is limited by the rate of bandwidth control. That is, the transmission rate of the data terminal D1 is determined by the transfer rate at the portal node (P) 100, and the transmission rate of the entire data terminal is determined by the bandwidth control rate.

  Similarly, the same is done for traffic coming from the outside.

The second embodiment of the present invention will be described below.
In the first embodiment of the present invention, the portal node (P) 100 performs bandwidth control. However, other cases may be considered where the access is performed by an access point (AP) or an external node on the wired side. For example, the node having the access point (AP) count management unit 107 is not limited to the portal node (P) 100 but may be the access point (AP) 200 or the access point (AP) 300.

  Even if it is not a TCP flow, it is effective for communication having congestion control. For example, the present invention can be used in control for communication having congestion avoidance control in a network having one portal.

The wireless LAN system of the present invention has the following features.
(1) In a wireless LAN multi-hop system having one portal, bandwidth control for non-priority traffic is performed, thereby securing a bandwidth for priority traffic.
(2) Counting the number of access points (APs), estimating the traffic volume of priority traffic, and performing bandwidth control for non-priority traffic.

  As described above, in the present invention, in a wireless LAN multi-hop network composed of one portal, the traffic flowing through the network is divided into two classes of priority / non-priority, and band control is performed for non-priority traffic.

  In a wireless LAN multi-hop network, there is a retransmission control in the MAC (Media Access Control) layer, which is a lower sublayer of the data link layer (second layer), and it is possible to monitor the traffic volume in real time and to reduce the traffic volume of the priority traffic. It is difficult to obtain accurately. In the present invention, by counting the number of access points (AP) to be connected, it is possible to accurately obtain the priority traffic band to be secured. In addition, it is possible to operate with only the number of access points (APs) regardless of the VoIP codec to be used.

  In the present invention, attention is paid to the fact that most of the data traffic to be subjected to non-priority traffic is TCP communication having a congestion avoidance function, and communication with the outside is the main. By performing bandwidth control at one location where traffic is concentrated with respect to non-priority traffic to be regulated, it becomes possible to keep the traffic amount of non-priority traffic below a certain level.

  As a result, it is possible to secure a bandwidth for priority traffic, and it is possible to control the amount of traffic flowing through the network more easily without requiring operations such as bandwidth control at a plurality of nodes. In a wireless LAN multi-hop network having one portal, the TCP flow with the outside passes through a common link, so this method is effective.

FIG. 1 is a conceptual diagram showing a network topology of the present invention. FIG. 2 is a block diagram showing a basic configuration of the portal node (P). FIG. 3 is a flowchart showing the operation of the present invention.

Explanation of symbols

100 ... Portal node (P)
DESCRIPTION OF SYMBOLS 101 ... Input link 102 ... Packet processing part 103 ... Priority queue 104 ... Non-priority queue 105 ... Band control part 106 ... Output link 107 ... Access point (AP) count management part 200, 300 ... Access point (AP)
201, 202, 203, 301, 302, 303 ... Wireless communication unit

Claims (9)

A priority queue that is a queue for priority traffic;
A non-priority queue that is a queue for non-priority traffic;
A bandwidth control unit connected to the non-priority queue and performing bandwidth control on the non-priority traffic in a wireless LAN multi-hop network to secure the bandwidth of the priority traffic ;
Count management unit for counting and managing the number of access points connected downstream in the wireless LAN multi-hop network
Holders of Bei said bandwidth controller, a network management apparatus for performing bandwidth control for estimating the traffic volume of the priority traffic based on the number of the access point the non-priority traffic.   The network management device according to claim 1,
  The bandwidth control unit determines a priority traffic bandwidth V based on the number of access points.
  Network management device. In the network management device according to claim 1 or 2,
The bandwidth control unit is a network management device that performs bandwidth control so that D ≦ B−V for a bandwidth control rate D, a bottleneck link bandwidth B, and a priority traffic bandwidth V. The network management device according to claim 3,
The bandwidth control unit performs bandwidth control so that the bandwidth control rate is set to D / 2 or less when the non-priority traffic flows bidirectionally in the network. A step of port Tarunodo is, at the start of transmission processing of the packet, to determine whether the packet in the priority queue exists,
If there is a packet in front Symbol priority queue, the portal node, sending a packet of the priority queue,
Unless there are packets before Symbol priority queue, the portal node, the step of checking whether the packet to the non-priority queue exists,
If there is a packet in front Symbol non-priority queue, the portal node comprises the steps of: transmitting rate of the non-priority traffic to determine whether it is less than the rate of bandwidth control,
If the transmission rate of the previous SL non-priority traffic the following rates of the bandwidth control, the portal node, sending a packet of the non-priority queue,
If the previous SL does not exist packets in non-priority queue, or if the transmission rate of the non-priority traffic is not less than the rate of the bandwidth control, the portal node, the steps of ending the transmission process of the packet,
Counting and managing the number of access points connected downstream;
A bandwidth control method comprising: estimating a traffic volume of priority traffic based on the number of access points and performing bandwidth control on non-priority traffic .   The bandwidth control method according to claim 5, wherein
  Determining a priority traffic band V based on the number of access points;
Further comprising
  Bandwidth control method. The bandwidth control method according to claim 6 or 7,
Rate D before Symbol band control, the bandwidth B of the bottleneck link, and the band V priority traffic, further bandwidth control method comprising the steps of performing a band control so that D ≦ B-V. The bandwidth control method according to claim 7 , wherein
When flowing before Symbol the non-priority traffic network bidirectionally, further bandwidth control method comprising the steps of performing a band control so that the rate of the bandwidth control and D / 2 or less. A program for causing a computer to execute the bandwidth control method according to any one of claims 5 to 8 .

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